Hey guys, I've decided to start collecting the parts needed for a BT build and I was hoping to get some advice from the members of the forum regarding fitment.

The unit I'm looking at is a Gen2 GTX 3071R 0.63 DBB without wastegate, so will be running a tial 38mm external on the manifold.

I'm wondering if there are any fitment problems when rear mounting the turbo as there are cast log manifolds available for around £100
The next option is an SPA bottom mount with wastegate on the top for £200
And CTS/TurboZentrum top mounts are around £500 but I do like the position of the wastegate port being at the side as it seems easy to loop around it with the downpipe. Plus having a massive turbo sticking out in your face would be fecking shweeeeeeeeetttt! Sorry inner 10 year old

I'll be making up my own downpipe so I'm not too worried about that as long as the turbo will physically fit in the space between the manifold and the bulkhead. I decided to go for the DDB turbo rather than the £100 journal bearing style, so if I can save on the manifold that would be nice.

Car is a Leon Cupra 180. Transverse. RHD.

@Marty Thanks for the reply. I see what you mean about the wastegate port. I know they do 2 bolt to v band adapter flanges etc, and I was planning to have a "screamer pipe" anyways. Good to know it would fit on a rear mount. Don't get me wrong I think the top mounts look awesome and a lot easier to make it all fit. I'm just trying to figure out what I can save on.

I wont be skimping on the turbo, or a set of "maxpeeding rods" that seem to have mixed reviews.
So I'm looking at:

£500 on the turbo
£400-£500 on rods
£100 for a fuel pump upgrade
£280 or so for bosch 630cc injectors
£150 or so for an ATP 3" tip, and that will need adapting to the 4" inlet on the gtx3071r
ARP Headbolts, gaskets, WMI, the list is soon piling up.
And I expect to pay probably £500+ for a tune as I doubt it is something I could do myself without pestering you guys all the time. I could just about dial in injectors and rescale a 3" maf with help, but as for adjusting boost pid, 5120 hack etc, I'm totally lost.

By spec every part to be swapped out what do you mean?

Do you mean let the tuner pick specific brands of injectors, map sensors etc?

My plan was to build it myself, but when it comes to the fine tuning, it's way out of my expertise right now.

I'm looking at genuine bosch 630cc injectors
1.9 TDI 4 bar map sensor
3" maf housing from the 225/vr6
APS 265 L/PH in tank pump
Tial 38mm external wastegate
R8 Coils

I can only imagine the issues with no start cars with all sorts of problems that turn up and make tuners want to hang themselves. But surely I can build it myself if I do it properly. It's mainly budget that is the issue for me. I couldn't justify sending it somewhere and paying tens of thousands to have it all built, when the only thing I can't do competently is the tuning side of things.

I know extensive work has to be done with KFMIRL and IOP with BT's, 5120 HACK, everyone says 3" maf housing but I thought the 3" maf housing was only good for around 350 bhp or around 292 g/s, Does that mean I need to be looking at 3.5" or 4" maf housings, or can you scale a 3" housing to read higher airflow with the right methods?

The time it would take to test it, upload logs, have someone look at it and then re-flash and log again, probably dozens of times to dial it all in would be no joke. But I would be more than happy to pay someone on the forum for their services when I get to that point. They could even work with me when it comes to compiling my parts list.

Honestly I think I'll try it myself. I should be able to scale the injectors to a decent level with a few runs and adjusting with logs. I'll do some more research into the different sized maf housings available and figure out how to scale them according to diameter difference I guess? Assuming the 3" wont be big enough. Run it under 20 psi until I get it all figured out and look into the 5120 another time. I'll be saving for a while to get the whole kit together anyway.

I don't use my car much and I've never been one to drive like an idiot on public roads and see how fast I can take blind corners. I just like to give it a good hit in 2nd to fourth or fifth every now and then. I can live with a bit of lag before it comes on boost because of the way I drive. Once I hit the limiter in 2nd and change up I'm going to be on boost from that point anyway.

I've found a nice manifold from SPA for a fair price, it's a twin scroll top mount cast manifold so I figured I might as well pick up a twin scroll exhaust housing for the turbo. I originally wanted a .63 but in the twin scroll they offer a .61, .78 and .82 & .83. What would you guys recommend. Would a twin scroll .78 spool like a single .63 but give more top end? Or would a .61 twin scroll be a nice balance of spool and top end on a gtx3071r? Obviously I'll be avoiding the 1.06 housings with the little 1,8t

What would you recommend? I'd like to make between 450-500 at the wheels. I like the idea of the .61 because I figured with a DBB turbo and a twin scroll .61 I should have some nice boost around 3.5k and not too much lag, it's just .61 seems a little small for a twin scroll, and I don't want to choke up the turbo too much. The are 2 options for gen 2 twin scroll housing trims on ebay. .61 and .83

What sort of cam are we talking, NA Cam or something a little more direct?

PS: Looking at some supertech inconel exhaust valves as I've heard they are a must for my power goals. I'd like to do double valve springs and titanium hats eventually, but I can keep the rpm at a safe level while I work out the base tune anyway.